Power management integrated circuits (power management ICs or PMICs) are used for managing the power requirement of a host system. A PMIC may be used in battery-operated devices, such as mobile phones, tablets, laptops, wearables, etc., to control the flow and direction of electrical power in the devices. The PMIC may perform a variety of functions for the device such as DC-to-DC conversion, battery charging, power-source selection, voltage scaling, power sequencing, etc. In some cases, a low-dropout (LDO) regulator and/or a block head switch (BHS) may be coupled to the PMIC for providing a supply voltage to one or more loads.
An LDO regulator is a voltage regulator that can regulate its output voltage even when the supply voltage of the LDO regulator is close to the output voltage. A block head switch (BHS) generally refers to a switch for coupling a voltage supply to a load. A BHS may have low resistance, thereby resulting in a low voltage drop across the BHS. BHSs may be used to couple a supply voltage provided by the PMIC to one or more loads. However, as a BHS is unable to regulate the supply voltage provided by the PMIC, the supply voltage applied to each load may be above the desired voltage of the load, reducing efficiency. On the other hand, LDO regulators can regulate a supply voltage, and thus, can be used to provide different supply voltages to each load, even from a single supply voltage provided by the PMIC. Therefore, when a single supply voltage is provided by the PMIC for different loads, an LDO and a BHS could be employed in parallel. If a first load is to be provided a supply voltage that is close to the supply voltage provided by the PMIC, then the BHS may be turned on and the LDO regulator may be turned off. However, if a second load is to be supplied a lower supply voltage than the supply voltage supplied by the PMIC, then the LDO regulator may be turned on and the BHS may be turned off, such that the LDO regulator can provide a regulated voltage supply to the second load.